//------------------------------------------------------------------------------
// <copyright file="SqlConnectionFactory.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------

namespace System.Data.SqlClient
{
    using System;
    using System.Data.Common;
    using System.Data.ProviderBase;
    using System.Collections.Specialized;
    using System.Configuration;
    using System.Diagnostics;
    using System.IO;
    using System.Runtime.Versioning;

    using Microsoft.SqlServer.Server;

    
    sealed internal class SqlConnectionFactory : DbConnectionFactory {
        private SqlConnectionFactory() : base(SqlPerformanceCounters.SingletonInstance) {}

        public static readonly SqlConnectionFactory SingletonInstance = new SqlConnectionFactory();
        private const string _metaDataXml          = "MetaDataXml";

        override public DbProviderFactory ProviderFactory {
            get {
                return SqlClientFactory.Instance;
            }
        }

        override protected DbConnectionInternal CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) {
            return CreateConnection(options, poolKey, poolGroupProviderInfo, pool, owningConnection, userOptions: null);
        }

        override protected DbConnectionInternal CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) {
            SqlConnectionString opt = (SqlConnectionString)options;
            SqlConnectionPoolKey key = (SqlConnectionPoolKey) poolKey;
            SqlInternalConnection result = null;
            SessionData recoverySessionData = null;
            SqlConnection sqlOwningConnection = owningConnection as SqlConnection;
            bool applyTransientFaultHandling = sqlOwningConnection != null ? sqlOwningConnection._applyTransientFaultHandling : false;

            SqlConnectionString userOpt = null;
            if (userOptions != null) {
                userOpt = (SqlConnectionString)userOptions;
            }
            else if (sqlOwningConnection != null) {
                userOpt = (SqlConnectionString)(sqlOwningConnection.UserConnectionOptions);                
            }

            if (sqlOwningConnection != null) {
                recoverySessionData = sqlOwningConnection._recoverySessionData;
            }

            if (opt.ContextConnection) {
                result = GetContextConnection(opt, poolGroupProviderInfo);
            }
            else {
                bool redirectedUserInstance       = false;
                DbConnectionPoolIdentity identity = null;

                // Pass DbConnectionPoolIdentity to SqlInternalConnectionTds if using integrated security.
                // Used by notifications.
                if (opt.IntegratedSecurity || opt.Authentication == SqlAuthenticationMethod.ActiveDirectoryIntegrated) {
                    if (pool != null) {
                        identity = pool.Identity;
                    }
                    else {
                        identity = DbConnectionPoolIdentity.GetCurrent();
                    }
                }

                // FOLLOWING IF BLOCK IS ENTIRELY FOR SSE USER INSTANCES
                // If "user instance=true" is in the connection string, we're using SSE user instances
                if (opt.UserInstance) {
                    // opt.DataSource is used to create the SSE connection
                    redirectedUserInstance = true;
                    string instanceName;

                    if ( (null == pool) || 
                         (null != pool && pool.Count <= 0) ) { // Non-pooled or pooled and no connections in the pool.

                        SqlInternalConnectionTds sseConnection = null;
                        try {
                            // What about a failure - throw?  YES!
                            // 



                            SqlConnectionString sseopt = new SqlConnectionString(opt, opt.DataSource, true /* user instance=true */, false /* set Enlist = false */);
                            sseConnection = new SqlInternalConnectionTds(identity, sseopt, key.Credential, null, "", null, false, applyTransientFaultHandling: applyTransientFaultHandling);
                            // NOTE: Retrieve <UserInstanceName> here. This user instance name will be used below to connect to the Sql Express User Instance.
                            instanceName = sseConnection.InstanceName;

                            if (!instanceName.StartsWith("\\\\.\\", StringComparison.Ordinal)) {
                                throw SQL.NonLocalSSEInstance();
                            }

                            if (null != pool) { // Pooled connection - cache result
                                SqlConnectionPoolProviderInfo providerInfo = (SqlConnectionPoolProviderInfo) pool.ProviderInfo;
                                // No lock since we are already in creation mutex
                                providerInfo.InstanceName = instanceName;
                            }
                        }
                        finally {
                            if (null != sseConnection) {
                                sseConnection.Dispose();
                            }
                        }
                    }
                    else { // Cached info from pool.
                        SqlConnectionPoolProviderInfo providerInfo = (SqlConnectionPoolProviderInfo) pool.ProviderInfo;
                        // No lock since we are already in creation mutex
                        instanceName = providerInfo.InstanceName;
                    }

                    // NOTE: Here connection option opt is cloned to set 'instanceName=<UserInstanceName>' that was
                    //       retrieved from the previous SSE connection. For this UserInstance connection 'Enlist=True'.
                    // options immutable - stored in global hash - don't modify
                    opt = new SqlConnectionString(opt, instanceName, false /* user instance=false */, null /* do not modify the Enlist value */);
                    poolGroupProviderInfo = null; // null so we do not pass to constructor below...
                }
                result = new SqlInternalConnectionTds(identity, opt, key.Credential, poolGroupProviderInfo, "", null, redirectedUserInstance, userOpt, recoverySessionData, pool, key.AccessToken, applyTransientFaultHandling: applyTransientFaultHandling);
            }
            return result;
        }

        protected override DbConnectionOptions CreateConnectionOptions(string connectionString, DbConnectionOptions previous) {
            Debug.Assert(!ADP.IsEmpty(connectionString), "empty connectionString");
            SqlConnectionString result = new SqlConnectionString(connectionString);
            return result;
        }

        override internal DbConnectionPoolProviderInfo CreateConnectionPoolProviderInfo(DbConnectionOptions connectionOptions){
            DbConnectionPoolProviderInfo providerInfo = null;

            if (((SqlConnectionString) connectionOptions).UserInstance) {
                providerInfo = new SqlConnectionPoolProviderInfo();
            }

            return providerInfo;
        }

        override protected DbConnectionPoolGroupOptions CreateConnectionPoolGroupOptions( DbConnectionOptions connectionOptions ) {
            SqlConnectionString opt = (SqlConnectionString)connectionOptions;

            DbConnectionPoolGroupOptions poolingOptions = null;

            if (!opt.ContextConnection && opt.Pooling) {    // never pool context connections.
                int connectionTimeout = opt.ConnectTimeout;

                if ((0 < connectionTimeout) && (connectionTimeout < Int32.MaxValue/1000))
                    connectionTimeout *= 1000;
                else if (connectionTimeout >= Int32.MaxValue/1000)
                    connectionTimeout = Int32.MaxValue;

                if (opt.Authentication == SqlAuthenticationMethod.ActiveDirectoryInteractive) {
                    // interactive mode will always have pool's CreateTimeout = 10 x ConnectTimeout.
                    if (connectionTimeout >= Int32.MaxValue / 10) {
                        connectionTimeout = Int32.MaxValue;
                    } else {
                        connectionTimeout *= 10;
                    }
                    Bid.Trace($"<sc.SqlConnectionFactory.CreateConnectionPoolGroupOptions>Set connection pool CreateTimeout={connectionTimeout} when AD Interactive is in use.\n");
                }

                poolingOptions = new DbConnectionPoolGroupOptions(
                                                    opt.IntegratedSecurity || opt.Authentication == SqlAuthenticationMethod.ActiveDirectoryIntegrated,
                                                    opt.MinPoolSize,
                                                    opt.MaxPoolSize,
                                                    connectionTimeout,
                                                    opt.LoadBalanceTimeout,
                                                    opt.Enlist);
            }
            return poolingOptions;
        }

        // SxS (VSDD 545786): metadata files are opened from <.NetRuntimeFolder>\CONFIG\<metadatafilename.xml>
        // this operation is safe in SxS because the file is opened in read-only mode and each NDP runtime accesses its own copy of the metadata
        // under the runtime folder.
        [ResourceExposure(ResourceScope.None)]
        [ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)]
        override protected DbMetaDataFactory CreateMetaDataFactory(DbConnectionInternal internalConnection, out bool cacheMetaDataFactory){
            Debug.Assert (internalConnection != null, "internalConnection may not be null.");
            cacheMetaDataFactory = false;

            if (internalConnection is SqlInternalConnectionSmi) {
                throw SQL.NotAvailableOnContextConnection();
            }

            NameValueCollection settings = (NameValueCollection)PrivilegedConfigurationManager.GetSection("system.data.sqlclient");
            Stream XMLStream =null;
            if (settings != null){
                string [] values = settings.GetValues(_metaDataXml);
                if (values != null) {
                    XMLStream = ADP.GetXmlStreamFromValues(values, _metaDataXml);
                }
            }

            // if the xml was not obtained from machine.config use the embedded XML resource
            if (XMLStream == null){
                XMLStream = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream("System.Data.SqlClient.SqlMetaData.xml");
                cacheMetaDataFactory = true;
            }
            Debug.Assert (XMLStream != null,"XMLstream may not be null.");

            return new SqlMetaDataFactory (XMLStream,
                                          internalConnection.ServerVersion,
                                          internalConnection.ServerVersion); //internalConnection.ServerVersionNormalized);

        }

        override internal DbConnectionPoolGroupProviderInfo CreateConnectionPoolGroupProviderInfo (DbConnectionOptions connectionOptions) {
            return new SqlConnectionPoolGroupProviderInfo((SqlConnectionString)connectionOptions);
        }


        internal static SqlConnectionString FindSqlConnectionOptions(SqlConnectionPoolKey key) {
            SqlConnectionString connectionOptions = (SqlConnectionString )SingletonInstance.FindConnectionOptions(key);
            if (null == connectionOptions) {
                connectionOptions = new SqlConnectionString(key.ConnectionString);
            }
            if (connectionOptions.IsEmpty) {
                throw ADP.NoConnectionString();
            }
            return connectionOptions;
        }

        private SqlInternalConnectionSmi GetContextConnection(SqlConnectionString options, object providerInfo) {
            SmiContext smiContext = SmiContextFactory.Instance.GetCurrentContext();

            SqlInternalConnectionSmi result = (SqlInternalConnectionSmi)smiContext.GetContextValue((int)SmiContextFactory.ContextKey.Connection);

            // context connections are automatically re-useable if they exist unless they've been doomed.
            if (null == result || result.IsConnectionDoomed) {
                if (null != result) {
                    result.Dispose();   // A doomed connection is a messy thing.  Dispose of it promptly in nearest receptacle.
                }

                result = new SqlInternalConnectionSmi(options, smiContext);
                smiContext.SetContextValue((int)SmiContextFactory.ContextKey.Connection, result);
            }

            result.Activate();

            return result;
        }

        override internal DbConnectionPoolGroup GetConnectionPoolGroup(DbConnection connection) {
            SqlConnection c = (connection as SqlConnection);
            if (null != c) {
                return c.PoolGroup;
            }
            return null;
        }

        override internal DbConnectionInternal GetInnerConnection(DbConnection connection) {
            SqlConnection c = (connection as SqlConnection);
            if (null != c) {
                return c.InnerConnection;
            }
            return null;
        }

        override protected int GetObjectId(DbConnection connection) {
            SqlConnection c = (connection as SqlConnection);
            if (null != c) {
                return c.ObjectID;
            }
            return 0;
        }

        override internal void PermissionDemand(DbConnection outerConnection) {
            SqlConnection c = (outerConnection as SqlConnection);
            if (null != c) {
                c.PermissionDemand();
            }
        }

        override internal void SetConnectionPoolGroup(DbConnection outerConnection, DbConnectionPoolGroup poolGroup) {
            SqlConnection c = (outerConnection as SqlConnection);
            if (null != c) {
                c.PoolGroup = poolGroup;
            }
        }

        override internal void SetInnerConnectionEvent(DbConnection owningObject, DbConnectionInternal to) {
            SqlConnection c = (owningObject as SqlConnection);
            if (null != c) {
                c.SetInnerConnectionEvent(to);
            }
        }

        override internal bool SetInnerConnectionFrom(DbConnection owningObject, DbConnectionInternal to, DbConnectionInternal from) {
            SqlConnection c = (owningObject as SqlConnection);
            if (null != c) {
                return c.SetInnerConnectionFrom(to, from);
            }
            return false;
        }

        override internal void SetInnerConnectionTo(DbConnection owningObject, DbConnectionInternal to) {
            SqlConnection c = (owningObject as SqlConnection);
            if (null != c) {
                c.SetInnerConnectionTo(to);
            }
        }

    }

    sealed internal class SqlPerformanceCounters : DbConnectionPoolCounters {
        private const string CategoryName = ".NET Data Provider for SqlServer";
        private const string CategoryHelp = "Counters for System.Data.SqlClient";

        public static readonly SqlPerformanceCounters SingletonInstance = new SqlPerformanceCounters();

        [System.Diagnostics.PerformanceCounterPermissionAttribute(System.Security.Permissions.SecurityAction.Assert, PermissionAccess=PerformanceCounterPermissionAccess.Write, MachineName=".", CategoryName=CategoryName)]
        private SqlPerformanceCounters() : base (CategoryName, CategoryHelp) {
        }
    }
}

